Morning Chronotypes Research Articles

The association between metabolic parameters and evening chronotype and social jetlag in non-shift workers: A meta-analysis.

The aim of the study was to evaluate the association between evening chronotype and social jetlag (SJL) with obesity, blood glucose and lipid levels in non-shift working adults. The databases of MEDLINE, EMBASE and Cochrane Reviews were searched for studies analyzing the metabolic parameters among groups of different chronotypes or SJL until Feb 2022. Weighted mean difference (WMD) and 95% confidence intervals (CI) were used to analyze the association between these parameters and chronotypes or SJL. A total of 27 studies were included in this meta-analysis. Compared with morning chronotype, the participants with evening chronotype had higher body mass index (BMI) (WMD= 0.44 kg/m2, 95%CI, 0.30 to 0.57 kg/m2, p<0.001), higher fasting blood glucose level (WMD= 5.83mg/dl, 95%CI, 3.27to 8.38 mg/dl, p<0.001), higher total cholesterol level (WMD= 6.63mg/dl, 95%CI, 0.69 to 12.56 mg/dl, p=0.03), and lower high density lipoprotein cholesterol (HDL-C) level (WMD= -1.80mg/dl, 95%CI, -2.30 to -1.31 mg/dl, p<0.001). Compared with the participants with small SJL, the participants with large SJL had larger waist circumference (WMD= 0.80cm, 95%CI, 0.77 to 0.83cm, p<0.001). Evening chronotype and SJL were associated with obesity and unfavorable metabolic parameters of glucose and lipid metabolism. https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42022303401.

Circadian Disruption and Colorectal Cancer Incidence in Black Women.

Animal and experimental studies suggest circadian disruption increases colorectal cancer risk, but evidence in humans is limited. We examined night shift work, chronotype, and residential position within a time zone, proxies for circadian disruption, in relation to colorectal cancer risk. Participants in the Black Women's Health Study, a prospective cohort of 59,000 Black American women established in 1995, reported history of night shift work and chronotype on follow-up questionnaires. Residential position within a time zone was estimated using participant addresses at each questionnaire cycle. Number of colorectal cancer cases and follow-up duration varied by analysis depending on timing of exposure assessment, ranging from 204 over the 2005 to 2018 night shift work study period to 452 over the 1995 to 2018 residential position study period. Cox proportional hazards regression was used to estimate multivariable-adjusted HRs and 95% confidence intervals (CI). Compared with never having worked a night shift, working a night shift for ≥10 years was associated with increased colorectal cancer risk (HR = 1.64; 95% CI, 1.01-2.66). However, shorter duration was not. The HR for evening versus morning chronotype was 0.96 (95% CI, 0.73-1.27). Westward position of residence within a time zone was not associated with colorectal cancer risk (HR per 5-degree longitude increase: 0.92; 95% CI, 0.82-1.03). Our findings suggest a possible increased risk of colorectal cancer associated with long duration night shift work; however, results require confirmation in larger studies. Circadian disruption from long-term night shift work may contribute to colorectal cancer development in Black women.

Independent and joint effect of chronotype and sleep duration on self-rated health in medical students

Objective: To investigate the independent and joint effects of chronotype and sleep duration on self-rated health in medical students. Methods: A cross-sectional study was conducted in 1 526 medical students selected through proportional stratified cluster random sampling from a medical university in Zhejiang province. A questionnaire survey was conducted to collect the information about their basic demographic characteristics, chronotype, sleep duration, and other lifestyle factors such as midnight snack, sedentary behavior, physical activity, meal time, and self-rated health. The independent and joint effects of chronotype and sleep duration on self-rated health were assessed by logistic regression model after controlling for confounding variables. Results: The numbers of the students with evening chronotype, neutral chronotype, and morning chronotype were 664 (43.5%), 442 (29.0%), and 420 (27.5%), respectively. Among the medical students, 42.8% (653) had poor self-rated health. Compared with those with the morning chronotype, the adjusted ORs for those with neutral chronotype and evening chronotype were 1.69 (95%CI: 1.23-2.31) and 2.43 (95%CI: 1.81-3.26), respectively, trend test P<0.001. Compared with those with sleep duration of 8 h or above per night, the adjusted ORs for those with sleep duration of 7 and ≤6 h per night were 1.40 (95%CI: 1.07-1.84) and 2.38 (95%CI: 1.69-3.37), respectively, trend test P<0.001. In the joint effect, compared with those with the morning chronotype and sleep duration of 8 h or above per night, the adjusted OR for those with evening chronotype and sleep duration of ≤6 h per night was 6.53 (95%CI: 3.53-12.09). Conclusions: Both evening chronotype and insufficient sleep were associated with increased odds of poor self-rated health in medical students, and they had joint effects. Therefore, it is necessary to promote early to bed, early to rise and adequate sleep in medical student to maintain their health.

Cross-sectional interrelationships between chronotype, obstructive sleep apnea and blood pressure in a middle-aged community cohort.

Chronotype is linked to adverse health measures and may have important associations with obstructive sleep apnea and blood pressure, but data are limited. This study aimed to determine the separate and combined associations of chronotype with obstructive sleep apnea and blood pressure in a middle-aged community population. Adults (n= 811) from the Raine Study (female=59.2%; age mean [range]=56.6 [42.1-76.6] years) were assessed for chronotype (Morningness-Eveningness Questionnaire), blood pressure and hypertension (doctor diagnosed or systolic blood pressure ≥ 140 mmHg and/or diastolic ≥ 90 mmHg), and obstructive sleep apnea at different in-laboratory apnea-hypopnea index thresholds (5, 10, 15 events per hr). Linear and logistic regression models examined relationships between chronotype and the presence and severity of obstructive sleep apnea, blood pressure, hypertension, and blood pressure stratified by obstructive sleep apnea severity at above-mentioned apnea-hypopnea index thresholds. Covariates included age, sex, body mass index, alcohol consumption, smoking, physical activity, sleep duration, anti-hypertensive medication, insomnia, and depressive symptoms. Most participants were categorised as morning (40%) or intermediate (43%), with 17% meeting criteria for evening chronotypes. Participants with apnea-hypopnea index ≥ 15 events per hr and morning chronotype had higher systolic (9.9 mmHg, p< 0.001) and a trend for higher diastolic blood pressure (3.4 mmHg, p= 0.07) compared with those with an evening chronotype, and higher systolic blood pressure compared with those with an intermediate chronotype (4.8 mmHg, p= 0.03). Across chronotype categories, no differences in systolic or diastolic blood pressure or odds of hypertension were found at apnea-hypopnea index thresholds of ≥ 5 or ≥ 10 events per hr. Among participants with apnea-hypopnea index ≥ 15 events per hr, systolic blood pressure is higher in those with a morning chronotype than evening and intermediate chronotypes. Assessment for morning chronotype may improve risk stratification for hypertension in patients with obstructive sleep apnea.

Study on the Changes in Circadian Rhythm Before and After Treatment and the Influencing Factors in Patients with Depression.

To investigate the circadian rhythms of patients with major depressive disorder (MDD) pre-treatment and post-treatment to analyse possible influencing factors. In this study, we recruited 154 patients in the acute phase of MDD from 10 psychiatric centers in the province. The patients were divided into a morning chronotype group (16-41 points), an intermediate chronotype group (42-58 points) and an evening chronotype group (59-86 points), according to the total scores obtained from the morningness-eveningness questionnaire (MEQ). They were treated randomly with antidepressants, either selective serotonin reuptake inhibitors or agomelatine, for 12 weeks and were evaluated using the MEQ, the 17-item Hamilton Depression Rating Scale (HAMD-17), the Hamilton anxiety scale, the Snaith-Hamilton pleasure scale (SHAPS), the multidimensional fatigue inventory (MFI-20) and the Pittsburgh sleep quality index at the baseline and then at 2, 4, 8 and 12 weeks. The results were analysed by Logistic regression analysis and repeated-measures analysis of variance. The baseline detection rates for the evening, intermediate and morning types were 14.93%, 56.5% and 28.57%, respectively. HAMD-17 scores were significantly lower at weeks 2, 4, 8, and 12 after treatment in patients with different concurrent phenotypes compared with those before treatment (P<0.05). There were significant differences in gender, age, body mass index, whether depression was first-episode, type of medication, baseline-MEQ and baseline-SHAPS in the chronotype change group compared with the post-treatment chronotype unchanged group (p<0.05). Logistic regression analysis showed that medication type (P=0.047), baseline MEQ (P=0.001) and baseline SHAPS (P=0.001) were risk factors for improvement in circadian rhythm after treatment for depression. Circadian rhythm disturbances can be adjusted to a normal pattern with effective antidepressant therapy. The medication type, baseline MEQ and baseline SHAPS scores were the influencing factors for the recovery of circadian rhythm disorders.

Photoperiodic stability and distribution of chronotypes in young residents of the North with different organization of activities

AIM: To assess individual subjective chronotypic properties in residents of Khanty-Mansiysk under the influence of such biotropic and social stress factors as regular daytime and aperiodically presented shift daytime and nighttime employment.&#x0D; MATERIALS AND METHODS: This study involved students (100 girls and 53 boys) of Khanty-Mansi Autonomous Okrug Yugra with a daily study load and employees of the Ambulance station (31 women and 26 men) in Khanty-Mansiysk, working in shifts. The photoperiodic chronotype stability was studied using the computer program Photoperiodic chronotype stability calculator (registration no. 2019661664) in the form of a mobile application for Android Photoperiodic stability index.&#x0D; RESULTS: The photoperiodic stability of the chronotype in women was: with regular daily employment 3.5 (1.56.0) arb. units, with shift work 1.0 (04.0) arb. units. The photoperiodic stability of the chronotype in men was: with regular daily employment 3.0 (1.04.0) arb. units, with shift work 1.5 (03.0) arb. units.&#x0D; Volunteers with a regular daytime job tended to choose to shift activities to the afternoon and refusing morning activity. In the group with shift work, the proportion of people preferring the morning type of work capacity was higher. In the group with shift and night work, there were no representatives of a definitely morning chronotype among women, and definitely an evening chronotype among men. In the summer season, male and female respondents, regardless of the production regime, showed an increase in the signs of the morning chronotype.&#x0D; CONCLUSION: The production and intersexual features of the chronotypological properties of the inhabitants of the North have been established. With the superposition of extreme climatic and geographical factors and social and production conditions, a general pattern of increased rigidity of the chronotype was recorded. Male and female respondents under different production regimes, when assessing subjective biorhythmic performance in the summer, demonstrated a shift toward the morning chronotype.

Influence of age, gender characteristics, chronotype on the expression of core clock genes Per1, Clock, Bmal1 and Cry1 in buccal epithelium.

Fourteen healthy volunteers with a healthy periodontium and oral mucosa (7 women and 7 men) were selected for participation in the trial. The buccal epithelium sampling was performed at 07:00 am and 07:00 pm in one day by cytological brush. The surveyed patients were examined chronotypically using the Horn-Ostberg test. The determination of the mRNA expression of the Per1, Clock, Bmal1, Cry1 genes was performed by quantitative real-time PCR. Statistical analysis was performed using two-way analysis of variance followed by Bonferroni post hoc tests. Per1 expression was higher in the morning, regardless of chronotype, age, and gender. The expression of the Clock demonstrated the prevalence of the evening in both chronotypes, in both men and women. Bmal1 was better expressed in the evening, regardless of age, gender, and chronotype. The expression of Cry1 did not show statistically significant differences between the indicators. The evening expression of Clock was higher in people with the evening chronotype than in people with the morning chronotype. The chronotype did not show any effect on the expression of Per1, Bmal1, and Cry1. Age and sex did not show any effect on the expression of the core clock genes.

Chronotype in bipolar disorder: Differences in sleep quality, social jet lag, physical activity, and diet

Introduction. People with bipolar disorder are at a higher risk of metabolic morbidity and mortality. Chronotype may play a significant role due to its effect on sleep quality, eating patterns, and physical activity. Objective. To compare sleep quality, social jetlag, physical activity, and diet, depending on the chronotype of people with bipolar disorder, and to determine the association between these variables. Method. Cross-sectional, comparative, correlational study. The sociodemographic and clinical characteristics of subjects were assessed. Chronotype was determined using the Composite Scale of Morningness while sleep quality was evaluated through the Pittsburg Sleep Quality Index. Social jet lag was calculated through the absolute difference between the midpoint of sleep on weekends and workdays. Physical activity was measured through the Bouchard Activity Record and diet was evaluated through a food frequency questionnaire. Comparative analyses were performed between chronotype categories and the association between variables was measured. Results. 116 subjects were included. Subjects with evening chronotype reported poorer sleep quality than those with morning chronotype. Eveningness was associated with lower sleep quality scores and more hours of sleep on workdays, as well as with higher consumption of cold meats, calories, and sodium. Trends indicate greater social jet lag and low physical activity levels among evening chronotypes. Discussion and conclusion. The effects of chronotype on study variables require further research to clarify this complex relationship and develop educational strategies to promote sleep hygiene, physical activity, and a healthy diet.

Morning chronotype and digestive tract cancers: Mendelian randomization study.

Morning chronotype has been associated with a reduced risk of prostate and breast cancer. However, few studies have examined whether chronotype is associated with digestive tract cancer risk. We conducted a Mendelian randomization (MR) study to assess the associations of chronotype with major digestive tract cancers. A total of 317 independent genetic variants associated with chronotype at the genome-wide significance level (P < 5 × 10-8 ) were used as instrumental variables from a genome-wide meta-analysis of 449 734 individuals. Summary-level data on overall and six digestive tract cancers, including esophageal, stomach, liver, biliary tract, pancreatic and colorectal cancers, were obtained from the UK Biobank (11 952 cases) and FinnGen (7638 cases) study. Genetic liability to morning chronotype was associated with reduced risk of overall digestive tract cancer and cancers of stomach, biliary tract and colorectum in UK Biobank. The associations for the overall digestive tract, stomach and colorectal cancers were directionally replicated in FinnGen. In the meta-analysis of the two sources, genetic liability to morning chronotype was associated with a decreased risk of overall digestive tract cancer (odds ratio [OR] 0.94, 95% confidence interval [CI]: 0.90-0.98), stomach cancer (OR 0.84, 95% CI: 0.73-0.97) and colorectal cancer (OR 0.92, 95% CI: 0.87-0.98), but not with the other studied cancers. The associations were consistent in multivariable MR analysis with adjustment for genetically predicted sleep duration, short sleep, insomnia and body mass index. The study provided MR evidence of inverse associations of morning chronotype with digestive tract cancer, particularly stomach and colorectal cancers.

Analyzing social perception of chronotypes within the stereotype content model

ABSTRACT In the present article, we attempted to analyze the social perceptions of morning and evening chronotypes using the framework of the stereotype content model which posits that all social impressions and group stereotypes form along two basic dimensions: warmth and competence. The participants (N = 1277; 53% women) completed the Composite Scale of Morningness (CSM) and a questionnaire measuring beliefs about social perceptions of Morning-types and Evening-types. Bottom 10%, middle 20% and top 10% of the CSM distribution (N = 501 individuals) were selected as representatives of ‘pure’ chronotypes: evening (‘E-types’), intermediate (‘N-types’) and morning (‘M-types’). In the entire sample, M-types were perceived as markedly more competent and marginally warmer than E-types. When we took into account the perceivers’ own chronotypes, only the perceptions reported by N-types were consistent with that pattern. M-type perceivers displayed analogic albeit markedly stronger positive views of their ingroups, whereas E-types believed that individuals sharing their diurnal preference are equally competent but more warm compared to M-types. It seems that social perceptions of chronotypes emerge as a composition of two effects: the socially shared stereotype (emphasizing high competence of M-types) and ingroup-serving biases, resulting in viewing people sharing the perceiver’s own chronotype in a more favorable way.

Bidirectional associations of sleep and discretionary screen time in adults: Longitudinal analysis of the UK biobank.

The direction of the association between discretionary screen time (DST) and sleep in the adult population is largely unknown. We examined the bidirectional associations of DST and sleep patterns in a longitudinal sample of adults in the general population. A total of 31,361 UK Biobank study participants (52% female, 56.1 ± 7.5 years) had two repeated measurements of discretionary screen time (TV viewing and leisure-time computer use) and self-reported sleep patterns (five sleep health characteristics) between 2012 and 2018 (follow-up period of 6.9 ± 2.2 years). We categorised daily DST into three groups (low, <3h/day; medium, 3-4h/day; and high, >4h/day), and calculated a sleep pattern composite score comprising morning chronotype, adequate sleep duration (7-8h/day), never or rare insomnia, never or rare snoring, and infrequent daytime sleepiness. The overall sleep pattern was categorised into three groups (healthy: ≥ 4; intermediate: 2-3; and poor: ≤ 1 healthy sleep characteristic). Multiple logistic regression analyses were applied to assess associations between DST and sleep with adjustments for potential confounders. Participants with either an intermediate (OR: 1.40; 95% CI: 1.15, 1.71) or a poor (OR: 1.16; 95% CI: 1.10, 1.24) sleep pattern at baseline showed higher odds for high DST at follow-up, compared with those with a healthy baseline sleep pattern. Participants with medium (OR: 1.40; 95% CI: 1.14, 1.71) or high DST (OR: 1.62; 95% CI: 1.30, 2.00) at baseline showed higher odds for poor sleep at follow-up, compared with participants with a low DST. In conclusion, our findings provide consistent evidence that a high DST at baseline is associated with poor sleep over a nearly 7 year follow-up period, and vice versa.

Linking sleep, political ideology, and religious observance: a multi-national comparison

Abstract Sleep is fundamental to life and essential to one’s health behavior, scholastic achievement, and work performance. Recent years have seen an increase in empirical investigations incorporating sleep research into political science. This study complements existing sleep-politics studies by examining the associations between chronotype (a person’s preferred time to sleep and wake up) and attitudinal and behavioral political outcomes (left–right ideology and social conservatism proxied by religious service attendance). We analyze representative samples from 10 national contexts (Finland, Greece, Ireland, Mexico, the Netherlands, New Zealand, the Philippines, Russia, South Korea, and Switzerland) to test our hypotheses. The results demonstrate that morning chronotype has significant links with political conservatism in six national contexts depending on model specification (most robustly in Switzerland). Unexpectedly, the morning chronotype may have links to liberalism in three other countries depending on model specification (most robustly in Russia). The results for religious observance are more uniform, indicating a link between morningness and greater religious observance across all cases in many specifications (excepting a reversed relationship in New Zealand in some models). Urbanization, seasonal effects, geographical characteristics, and religious denominations are explored as potential confounders.

Assessment Of Sleep Quality By The Athlete Sleep Screening Questionnaire In Chinese Collegiate Athletes

Purpose: This study aimed to characterize sleep quality and to explore the factors that are associated with the severity of sleep difficulty among Chinese collegiate athletes. Methods: Sleep quality and associated factors were assessed by the Athlete Sleep Screening Questionnaire (ASSQ) in college athletes (n = 395, 73.6% response rate, aged 18 to 32 years, 47.6% female, 22.5% were master level, 47.6% national level and 29.9% second level in 15 different sports events). A sleep difficulty score (SDS) and level of sleep problem (0-4, none; 5-7, mild; 8-10, moderate; 11-17, severe) were used to classify participants. In addition, sports-related information such as sports events and training years were collected. Categorical variables were analyzed by Chi-squared (ꭓ2) or fisher’s exact test. An ordinal logistic regression analysis was used to explore factors with poor sleep (SDS > 8). Results: Approximately 14.2% of participants were found to have moderate to severe sleep problem (SDS > 8). When athletes travelled to participate in sports competitions, those who have experienced sleep disturbance were more diagnosed in the moderate-to-severe problem category than those without sleep disturbance (11.4% Vs. 2.8%, ꭓ2, 27.5; P < 0.001). While athletes who experienced daytime dysfunction when traveling fell more into the moderate-to-severe sleep problem category than athletes without daytime dysfunction (7.6% Vs. 6.6%, ꭓ2, 20.7; P < 0.001). No significant difference was found in SDS category between gender, sports level and sports events (All P > 0.05). Athletes with evening chronotype were more likely to report worse sleep compared to athletes with morning chronotype (OR, 2.25; 95%CI, 1.44 - 3.52; P < 0.001). For each additional year of age, there was an increase in odds ratio for poor sleep quality (OR1.15; 95% CI, 1.04 - 1.26; P = 0.004). However, increasing each additional year of training reduced the odds ratio for poor sleep quality (OR,0.95; 95% CI, 0.91 - 0.99; P = 0.044). Conclusion: To improve sleep health in collegiate athletes, chronotype, travel-related issues, age and training years should be taken into consideration in sleep counseling.

Do differences in chronotypes affect sleep and health-related quality of life of nursing students? A cross-sectional study

ABSTRACT Nursing students experience higher levels of stress and more sleep-related problems than other students; however, the relationship of chronotype to nursing students’ sleep status and health-related quality of life (HRQOL) is unclear. This cross-sectional, observational study investigated whether chronotype affected Japanese nursing college students’ sleep and HRQOL. Nursing students completed the Attribute Questionnaire about Subject Background, Japanese Version Morningness‒Eveningness Questionnaire (MEQ), Munich Chrono-Type Questionnaire‒Japanese Version (MCTQ), Japanese Version of the Pittsburgh Sleep Quality Index (PSQI), SF-12v2 Standard, Japanese Version 2.0 (SF-12), Japanese Translation of Profile of Mood States 2nd Edition‒Adult Short (POMS2). Of the 241 students (mean age 20.16 ± 1.80 years; 80.9% female), 80 (33.2%) had evening, 142 (58.9%) had intermediate, and 19 (7.9%) had morning chronotype. The overall total PSQI score was 6.86 ± 2.97. Additionally, 141 students (64.1%) scored ≥ 6, suggesting disturbed sleep. Approximately 80% of the evening chronotype students had a total PSQI score of 8.34 ± 3.11, clearly indicating disturbed sleep. Sleep-related parameters (total PSQI score, bedtime, sleep latency, wake-up time, sleep duration, social jetlag) were worse in evening than in other chronotypes. SF-12 and POMS2 did not differ among chronotypes. Thus, evening chronotype nursing students require sleep-related support from early on.

Shift Work and the Risk of Cardiometabolic Multimorbidity Among Patients With Hypertension: A Prospective Cohort Study of UK Biobank.

BackgroundAlthough the association between shift work and individual cardiometabolic diseases has been well studied, its role in the progression to cardiometabolic multimorbidity (CMM) remains unclear. In this study, we investigate the association between shift work and the incidence of CMM in patients with hypertension.Methods and ResultsThis study is a population‐based and prospective cohort study on 36 939 UK Biobank participants. We used competing risk models to examine the association between shift work and the risk of CMM, which was defined as coexistence of hypertension and diabetes, coronary heart disease, or stroke in our study. We also investigated the association between the frequency and duration of shift work and CMM risks. In addition, we conducted a cross‐classification analysis with the combination of frequency and duration of shift work, chronotype and sleep duration as the exposure metrics. During a median follow‐up of 11.6 years, a total of 5935 participants developed CMM. We found that usually/always night shift workers were associated with a 16% higher risk of CMM compared with day workers (hazard ratio [HR], 1.16 [95% CI, 1.02–1.31]). We also found that a higher frequency of night shifts (>10/month) was associated with increased risk of CMM (HR, 1.19 [95% CI, 1.06–1.34]) that was more pronounced for >10/month in combination with a morning chronotype or <7 hours or >8 hours of sleep duration (HR, 1.26 [95% CI, 1.02–1.56]; HR, 1.43 [95% CI, 1.19–1.72], respectively).ConclusionsWe find that night shift work is associated with higher CMM risk in patients with hypertension.

Association of Japanese Breakfast Intake with Macro- and Micronutrients and Morning Chronotype.

(1) Background: Dietary intake may have a remarkable effect on sleep because skipping breakfast and having a late dinner affects many sleep parameters. Breakfast is the most important meal of the day for children and adults to maintain morning chronotype. We examine whether breakfast style is associated with nutrient intake and sleep factors. (2) Methods: This cross-sectional analysis, with a large sample size of 2671 (766 men and 1805 women aged 20–60 years after data brush-up), was based on data obtained from an online survey. Correlation analysis was performed using Spearman’s rank correlation test. The Kruskal–Wallis’s test followed by post hoc Dunn’s multiple comparison test was used to evaluate the interaction between sleep factors and breakfast categories. Multiple regression analyses were performed to identify variables associated with multiple confounding factors. Dietary data were analyzed using approximately one-month average dietary records from the application. The basic characteristics of the participants (age, sex, and BMI) and other lifestyle-related factors (sleep and physical activity) were obtained accordingly. Sleep parameters including the timing of weekday sleep onset, weekday wake-up, weekend (free day) sleep onset, weekend wake-up, sleep, and midpoints of sleep phase were calculated for each participant. We categorized participants’ breakfast types into five groups: (1) Japanese meal, where breakfast may contain Japanese ingredients such as rice; (2) Western meal, where breakfast may contain bread; (3) alternating eating patterns of Japanese and Western meals; (4) cereals and supplements, where breakfast may contain cereals or supplements and energy bars; and (5) skipped breakfast (no breakfast). (3) Results: The midpoint values of the sleep phase on weekends adjusted for sleep debt on work days (MSFsc) related to chronotype were higher in women, suggesting that they may prefer eveningness. Participants with obesity, young age, and low physical activity preferred eveningness with longer sleep durations. Intake of Japanese-style breakfast was significantly associated with early wake-up time on both weekdays and weekends. Cereal-style breakfast intake was significantly associated with late wake-up on both weekdays and weekends. Intake of macronutrients such as protein, fat, carbohydrate, and sodium at breakfast time was positively and strongly associated with the intake of Japanese breakfast, whereas macronutrients were negatively associated with the intake of cereal breakfast. Among micronutrients, vitamin K was positively correlated with Japanese breakfast and negatively correlated with cereal breakfast; (4) Conclusions: Japanese-style breakfast is associated not only with morning preference but also with high intake of macro- and micronutrients.

Chronotype, circadian rhythm, and psychiatric disorders: Recent evidence and potential mechanisms.

The circadian rhythm is crucial for physiological and behavioral functions. Chronotype, which represents individual preferences for activity and performance, is associated with human health issues, particularly psychiatric disorders. This narrative review, which focuses on the relationship between chronotype and mental disorders, provides an insight into the potential mechanism. Recent evidence indicates that (1) the evening chronotype is a risk factor for depressive disorders and substance use disorders, whereas the morning chronotype is a protective factor. (2) Evening chronotype individuals with bipolar disorder tend to have more severe symptoms and comorbidities. (3) The evening chronotype is only related to anxiety symptoms. (4) The relationship between chronotype and schizophrenia remains unclear, despite increasing evidence on their link. (5) The evening chronotype is significantly associated with eating disorders, with the majority of studies have focused on binge eating disorders. Furthermore, the underlying mechanisms or influence factors are described in detail, including clock genes, brain characteristics, neuroendocrinology, the light/dark cycle, social factors, psychological factors, and sleep disorders. These findings provide the latest evidence on chronotypes and psychiatric disorders and serve as a valuable reference for researchers.

Association between Chronotype, Physical Activity and Sedentary Behaviour: A Systematic Review

Background: The aim of this systematic review is to compile and assess the scientific evidence about the relationship between chronotypes and physical activity (PA). Methods: A systematic review was executed using a structured electronic search in PubMED, Cochrane Library, PsycInfo and Trip Database. The searches employed keywords such as chronotype, sleep, acrophase, chronotype preference, morningness, physical activity and sedentary, using MeSH terms. JBI critical tools were used to appraise methodological aspects. Results: This systematic review includes 23 studies and a total of 505,375 participants. The results show that evening chronotypes are associated with less PA and more time in sedentary activities. It occurs independently of the instruments used to collect information about chronotype and PA. Nevertheless, this association could be mitigated in young populations and university stages. Conclusions: The chronotypes are clearly associated with the PA level and the sedentary behaviour, especially in the population over their mid-twenties. Evening chronotypes are associated with less PA and more time in sedentary activities compared to morning chronotypes.

Association between chronotype, sleep pattern, and eating behaviours in a group of Italian adults

A cross-sectional study was conducted to assess the possible relationship between chronotype, sleeping, and eating patterns in 74 Italian adults (71.6% women). Based on Morningness-Eveningness Questionnare (MEQ) score, participants were classified as morning (n = 24), intermediate (n = 25), and evening (n = 25) chronotypes. From analysis, no significant differences among chronotypes emerged for sleep habits. As to eating behaviours, the evening subjects showed a significant (p < 0.05) shift towards later hours of the day in the consumption of all meals, except dinner. In addition, the evening subjects had a later midpoint of energy intake (EI) of about 35 min and 1 h (p < 0.001), respectively, than the intermediate and morning subjects. Analysing the diet quality, morning subjects reported significantly (p = 0.030) lower consumption of sweets and sweeteners, and significantly (p = 0.035) lower intake of ultra-processed fats and seasonings. Evening subjects showed a significant delay in EI during the day, while morning subjects reported a better-quality diet.

Effects of Interrupted Daily Routine Due to COVID-19 on Circadian Chronotype and Leisure Time Physical Activity.

Circadian chronotype is dependent on many factors including age, physical activity participation, eating and sleeping patterns, and typical schedule. Recently, the COVID-19 pandemic resulted in schedule changes for most individuals. Therefore, the purpose of this study is to examine whether sport participation influences circadian chronotype and physical activity and whether COVID-19 restrictions have impacted chronotype scores. Briefly, 128 physically active males (n = 62) and females (n = 66) between 18 and 55 years old (24.7 ± 7.1) completed a survey consisting of demographics information, the Morningness–Eveningness Questionnaire (MEQ), and the Godin Leisure Time Physical Activity Scale (LTPA). Participants were asked to answer relevant questions about their habits/preferences before and after COVID-19-related restrictions were implemented. MEQ scores categorized individuals into morning (MT), intermediate (IT), and evening (ET) chronotypes. Three-way (pre-COVID-19 chronotype x sport participation x time) repeated measures ANOVA was conducted to evaluate differences in MEQ and LTPA. A significant main effect of time was found for MEQ (p = 0.018) and LTPA (p = 0.002), indicating changes following COVID-19. A significant time x chronotype interaction was shown for MEQ (p < 0.001) with MT (p < 0.001), IT (p = 0.044), and ET (p = 0.044) individuals indicating chronotype-specific changes following COVID-19. LTPA was decreased and MEQ scores changed following COVID-19, with shifts toward IT scores.